【推荐2】Experiment: A Steam-Proof Mirror

Have you noticed that after you take a warm shower or bath, the bathroom mirror is covered with tiny water droplets (水滴) that look like fog?

Here is a cure for foggy mirrors.

You will need

✮ Bathroom with mirror and shower or bathtub in the same room

✮ Small bottle of glycerin (甘油) (sold in drugstores)

✮ Liquid glass cleaner

✮ Paper towel

Do this

THE PROBLEM

Take a long, warm shower or bath with the door closed. Look closely at the mirror and wipe the water droplets with your finger. If the mirror is very clean, it will not get very foggy; the problem of a steamed- up mirror is worse when the mirror is dirty or dusty.

SOLVING IT

✮ Clean half of the mirror with glass cleaner and paper towels, and let it dry.

✮ Use a clean paper towel to rub some glycerin around on the half of the mirror you cleaned until it is covered with a thin layer.

The next time someone takes a long shower or bath, see what the mirror does.

What happened?

The half of the mirror covered with glycerin will not get foggy. That is because specks (微粒) of dust on the surface of the glass give the tiny water droplets a place to form. The glass cleaner removed any dust on the mirror and the glycerin gave the mirror a slick (光滑的) surface that didn’t collect dust; the water droplets had no dust particles to form on.

【推荐3】The body gives off many gases. Although some smells may signal a need to bathe or that you ate a certain meal, other gases might point to serious disease. Now, researchers have come up with a system that uses earmuffs to catch the disease-signaling gases. Doctors could get the information as patients wear a set of earmuffs. Results could be ready within minutes.

“The ear is a good place to monitor,” explains Johnson, a biomedical engineer. The ear’s skin is fairly thin, he notes. So gases don’t have to travel far to get out of the blood and escape through skin pores.

To collect the gases, Johnson and his team selected earmuffs that make a tight seal with the head. These are the type people often wear to protect the ears from loud noise. His team made two holes in the muff covering one ear. A tube slowly pumped air in one hole. Another tube pulled air out of the second hole and sent it to a sensor.

In their tests, the team found that they could measure changes in the amount of alcohol coming from the skin of the ear. It could work much like a Breathalyzer that police use to test people for driving drunk. The team invited three men. Each had to avoid drinking alcohol for at least three days before taking part. Once in the lab, these men wore the earmuffs and sat for 10 minutes as the system recorded normal gas levels leaving their ears. Afterward, the men drank a big amount of alcohol. About 7 minutes later, the earmuff system tested out a rise in alcohol leaving the skin. After 50 minutes, alcohol levels reached the peak and continued falling until the test was over.

The team then measured other gases by changing out the sensor. With the right sensor, their earmuff system could test out disease. Later, they replaced the earmuffs with a one-eared version to make it a bit more comfortable.

Johnson imagines another possible benefit. The earmuff system could help doctors tell whether a child’s ear infections have been caused by bacteria or a virus. How? Each type of infection exudes different gases. That, in turn, could guide how doctors cure the disease.

【推荐3】My heroes are the Singapore Women’s Everest Team. In 2009, they became the first all-women team to climb Mount Everest. The team of six young women trained for seven years before they climbed the mountain. It was difficult for them to train because Singapore doesn’t have any snow or any mountains. But they didn’t stop, and in the end they made it. I really admire them.

———Lance Reed,16, from Britain

I admire the Salwen family. In 2006, they decided to sell their house and give half of the money to charity(慈善). I really respect them because they gave their money to people in need.

—William Kloster, 17, from Canada

I really admire Steve Jobs, the former CEO of Apple. He invented a new kind of technology. Steve Jobs created a successful business in IT. I was very sad when he died in October 2011. I respect him because he changed the way people use technology all over the world.

——Richard Hale, 18, from Australia

My mum, Mary Evans, is a real hero. I have a very big family, with two brothers and three sisters. My mum works very hard every day to look after us, and she is very busy. She always makes time for everyone and she always listens to me if I have a problem. I really respect my mum.

——Mark Sterling, l7, from America